Yes, stomach issues are often associated with your solar plexus chakra, the third chakra. This is your area of power and confidence. Do you have a strong and stable self-identity? Are you able to stand up for yourself in confident in your opinions and decisions? Do you feel like you have adequate control over your life? There are many ways to balance every chakra, but some simple ones for now include eating more yellow foods, practicing the breath of fire, and practicing the yoga asanas of bow pose and Cobra pose. I hope this helps! My solar plexus chakra is one that I struggle to keep in balance as well, so I feel your pain!